CHICAGO — Kyle Hendricks began the season as the Cubs’ No. 5 starter. He’s on pace to finish it as the major league’s ERA leader and — if manager Joe Maddon has his way — potentially with an even bigger trophy.

Hendricks threw seven dominant innings to lower the majors’ best ERA to 2.09 and Anthony Rizzo homered to lead the Cubs past the Pittsburgh Pirates 3-0 on Tuesday night for Chicago’s 21st victory in August.

“He has to be in Cy Young contention,” Maddon said. “Put the radar gun in your back pocket and look at what he’s doing. There has to be strong consideration, not just consideration.”

Hendricks (13-7) allowed three hits and has given up three or fewer runs in 18 straight starts. He didn’t allow a hit until Gregory Polanco’s bloop to left-center in the fifth and faced the minimum 17 batters until John Jaso’s two-out double in the sixth.

Not bad for a guy who doesn’t often hit 90 mph with his fastball.

“He’s not the guy who’s getting away with plus-plus stuff. He’s just executing his game plan and he knows how to attack hitters,” Rizzo said. “He studies hitters and he went to Dartmouth and he has a really good education. So he out-tricks guys.”

Rizzo belted a two-run homer off Chad Kuhl (3-2) in the first and Miguel Montero added an RBI single an inning later as the Cubs improved to 84-47 despite only five hits.

Carl Edwards Jr. worked the eighth and Aroldis Chapman hit 103 mph in a perfect ninth to finished the four-hitter for his 31st save. The Cubs improved to 21-6 this month, one win shy of the best August in franchise history set in 1932.

Hendricks is well ahead of No. 2 Madison Bumgarner of San Francisco (2.49) in the ERA race. He only struck out four, but the Pirates had little solid contact as he kept them off-balance with a mix of pitches, including two- and four-seam fastballs.

“My fastball command was really good,” Hendricks said. “My curveball may have been the best it’s been all year. I threw a lot of good ones today.”

Andrew McCutchen’s one-out single in the seventh was the other hit off the right-hander. Hendricks is seeking to become the first Cubs pitcher to win the major league ERA title since Bill Lee in 1938.

Since Sept. 1, 2015, Hendricks is 18-7 with a 2.25 ERA, Cy Young Award-type numbers.

“Where I was at last year and my goals coming into this year, what I was trying to do, I definitely didn’t see myself as being a part of that,” Hendricks said. “I had my sights set a little lower.”

Kuhl, in his ninth major league start, allowed three runs and four hits in five innings as the Pirates lost their second straight after winning four in a row.

Jordy Mercer doubled with two outs off Edwards in the eighth before pinch-hitter Matt Joyce flied deep to center to end Pittsburgh’s best threat.

The Pirates fell 2 1/2 games behind St. Louis for the second NL wild-card as they flailed away against Hendricks.

“The command, the execution,” manager Clint Hurdle said. “I thought I was back in 1987 with Greg Maddux on the mound.”

TRAINER’S ROOM

Pirates: RHP Gerrit Cole (elbow inflammation) played catch, a day after being put on the 15-day disabled list. He could return as soon as Sept. 9. “Hopefully, (the rehab) will go quickly,” Cole said. . INF Jung Ho Kang (shoulder), working out with Indianapolis, is expected to begin an official rehab stint with the Triple-A team this week.

Cubs: RHP John Lackey (shoulder) will throw a bullpen session Thursday. If it goes well, he could start Sunday vs. San Francisco.

SUSPECT FIELD

A large chunk of the outfield in center and right fields was re-sodded and looks chewed up after Wrigley Field hosted Pearl Jam and Billy Joel concerts while the Cubs were away.

“It’s like a field after a concert,” RF Jason Heyward said.

UP NEXT

RHP Jason Hammel (13-7, 3.21) was moved up to start Wednesday night’s series finale against RHP Ryan Vogelsong (3-3, 3.02). LHP Mike Montgomery was pushed to Thursday. Hammel was lifted after allowing three runs in 2 1/3 innings Saturday. “He wants to get back out there,” Maddon said.